diff --git a/git/hooks/pre-commit b/git/hooks/pre-commit
index 877b9ad..fb7bf0b 100755
--- a/git/hooks/pre-commit
+++ b/git/hooks/pre-commit
@@ -74,4 +74,42 @@ if echo "$added_lines" | grep -qE "(password|secret|token|api_key)[[:space:]]*=[
     fi
 fi
 
+# ── Repo-declared checks ──────────────────────────────────────── (REVIEWED-100)
+# This hook is global to every repo (core.hooksPath), so it must hold no repo
+# knowledge. A repo opts in by declaring `.precommit-triggers` at its root:
+#
+#     <git pathspec> [more pathspecs] | <command>
+#
+# If the staged diff touches a declared pathspec, the command runs and a non-zero
+# exit refuses the commit. Path matching is delegated to git's own pathspec
+# engine rather than reimplemented here.
+#
+# Deliberately dependency-free — no yq, no python. A global convention that needs
+# a toolchain silently fails to travel to the next machine or repo, and a check
+# that silently does not run is worse than no check, because its absence reads as
+# a pass. That is why this departs from the YAML used by data python tools read.
+repo_root="$(git rev-parse --show-toplevel 2>/dev/null || true)"
+triggers_file="${repo_root:-.}/.precommit-triggers"
+if [ -n "$repo_root" ] && [ -f "$triggers_file" ]; then
+    # fd 3, so a check that reads stdin cannot swallow the rest of this file
+    while IFS='|' read -r paths cmd <&3 || [ -n "${paths:-}" ]; do
+        case "${paths%%[![:space:]]*}${paths#"${paths%%[![:space:]]*}"}" in \#*) continue ;; esac
+        cmd="$(printf '%s' "${cmd:-}" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')"
+        [ -n "$cmd" ] || continue
+        # shellcheck disable=SC2086 — word splitting is intended: multiple pathspecs
+        if [ -z "$(git diff --cached --name-only -- $paths 2>/dev/null)" ]; then
+            continue
+        fi
+        echo -e "${YELLOW}Staged change touches [${paths# }] — running declared check:${NC} $cmd"
+        if ! ( cd "$repo_root" && eval "$cmd" ) < /dev/null; then
+            echo -e "${RED}Declared check FAILED — commit refused.${NC}"
+            echo "  declared in: .precommit-triggers"
+            echo "  command:     $cmd"
+            echo "  --no-verify bypasses this; it is a tripwire, not a boundary."
+            exit 1
+        fi
+        echo -e "${GREEN}Declared check passed.${NC}"
+    done 3< "$triggers_file"
+fi
+
 echo -e "${GREEN}Pre-commit checks passed!${NC}"